Air mask



H. A. BRAND AIR MASK July 9, 1935.'

Filed Aug. 30, 1953 Patented vJuly 9, 1935 UNITED STATES PATENT OFFICE f 'i Y 2,007,440

AIR MASK nenry A. Brand, Michigan city, Ind. Application August 30, 1933, Serial No. 687,450

' adminis. (o1. 12s-146) ,My invention relates to air. masks worn by artisans'engag'ed 'in :occupations'where dust and dangerous fumes orrgases are encountered; the mask being'intendedto' encase the nose and mouthlof 'theweareror user and adapted to be connected with asuitable Asource of air under pressure.

The" invention has for its object the provision of va mask vof rthe character mentioned whereby a substantiallypositive pressure within the mask may be maintained; provided with means wherebyprper dissipation of the pressure of the ingoing air will occur and `a diffusion of the air within the mask produced.

Another obj ectof the invention is the provision of a construction whereby ingress of dust -particles orfunies" through the exhaust outlet will 'be 'prevented ,and at the same time improper inhalation through the `exhaust outlet also made impossible. l l

"These objects andother objects andV advantages'ofnfiy invention, as well as the structural vfeatures by means of which these objects and advantages are obtained, will be readily comprehended' from the following detailed description of the accompanying drawing, wherein- Figure 1 is an inside or rear View of the device in elevation with a portion of the air line broken away.l

Figure 2 is a vertical sectional view.

The face-engaging portion comprises a suitable rubber cushion I of proper configuration so as to t over the nose and about the mouth of the user and effect a substantially air sealing relation with the face of the user. This cushion may be of the well known types at present in use, namely either of the inflated or noninflated type as desired. These cushions are made to be removably attached to the metallic shell II of the mask; the cushion or the shell-engaging portion thereof being usually of such dimensions relative to the face side of the shell II as to necessitate the cushion being stretched over the shell and have snug fitting relation therewith as shown in Figure 2. The shell II is somewhat cup-shape and has a forward end wall I2 shown provided centrally with an outwardly pressed or dished portion I3 shown provided with a plurality of openings I4.

The forward wall I2 is provided with a forwardly projecting inverted V-shape hood portion I; the top and two sides whereof are intimately secured to the end wall I2 and surround the perforations I4 in the dished or raised portion I3 of the end wall; the lower flared end of the hood I5 being preferably disposed in a plane beneath that o-f the openings ill, and being open to the atmosphere. Pendently secured in the upper end of the hood I5 is a flap Valve I 6 which is adapted to completely cover the openings i4; the valve 5 IE being held against too far opening by a suitable spring as at Il. The valve i6 is loosely hung at its upper end so as to be free to swing about its horizontally disposed pivot I8.

The bottom or lower wall of the shell l I is pro- 10 vided with a tube Ii) intimately secured at its upper end to the shell. The tube I 9 extends downwardly from the shell and tapers toward its lower end to which an air Lline Z is secured; the line 2i) leads from a suitable source of compressed 15 air. The tube I, as more clearly shown in Figure 2, gradually ares toward the upperV end where it is provided with guard wires 2l which are bowed upwardly and spaced from the upper end of the tube I9. These guard wires 2l provide r20 a cage. whereby a discvalve 22 is held against displacement while permitting the disc to move upwardly through the action of the incoming air. `In order to ensure proper seating of the disc, it is shown provided on the bottom with a depending pin 23.

Arranged within the air tube I9, adjacent one side thereof, is a smaller tube 24.

This tube 2f extends from the lower end of tube I9 and passes upwardly beyond the upper end 30 of tube I9 to a point substantially opposite the center of the perforated portion I3 in the front wall of the shell l I. The upper end of tube 24 is preferably arranged at a distance from the wall I2; with the upper end closed as shown at 25, with 35 the lower surface of the end closure preferably ished or curving toward the forward side of tube 261 which is provided with an outlet opening 26; the arcuate lower surface of end closure 25 directing the air toward the outlet opening 26 and 40 causing the jet of air to be directed toward the exhaust holes I4.

The air tube 24 is preferably of the same diameter throughout and its inlet end is preferably about an eighth of an inch removed from the outer end of the main air tube i9. With tube 2li communicating with and extending directly from the air line or inhalation tube of the mask a substantially constant air line pressure in the mask is maintained; the air discharged from the outlet 2S is directed toward the exhalation outlet and expands adjacent thereto and aids in discharging the vitiated air from the mask.

The air coming into the mask through inlet tube I9 is not only allowed to somewhat expand 55v valve 22 also prevents dust particles from enter-Y ing the intake tube in the event of air line failure and improper application of the mask to the face whereby dust particles would be permitted entering around the cushion and hence no dust partieles can drop into the air inlet tube Aand to ulti'- mately be blown back into the mask and therefore into the wearers nostrils.

With valve I6 hingedly secured at its top in the housing or hood, it acts as a swinging check valve against inhalations through openings I4. The normal opening limit of this valve is controlled by the spring I'I which prevents the valve from falling or swinging too far open, as might occur in certain positions of the wearers head. If the swing valve I6 was allowed to drop forward against the front wall oi the housing or hood I5 while the user is in a stooping position, it would prevent proper closing oi the valve by the inhalation of the wearer and as a result there would be an intake of dust laden air through the exhaust openings. The spring I'i yieldingly maintains the free swinging valve i6 in sufficiently close proximity to the exhaust openings where inhalation will cause the valve to move to and remain in closed position. On the other hand, the spring Il is such and so arranged that in the event of too great a now of incoming air from the air line, the spring will permit the exhaust valve to move to an abnormal open position and compensate for the excess air volume.

The exhaust outlet involves a suilicient number of holes I4. Except for the face cushion I my improved mask is made entirely of metal; while the cushion is preferably removably secured on the perimeter of the shell I I.

The exemplification is believed to be the best embodiment of the invention which, however, may have expression in certain modifications without departing from the spirit of the invention as deiined in the appended claims.

What I claim is:

1. An air mask of the character described comprising a shell open at one end to fit about the 10 nose and mouth while the opposite end wall is provided with an exhaust opening; an air inlet in a side wall provided with an air expanding tube tapering away from the inlet and adapted to( be connected with an air supply line; a selfseating disc seatable on said air inlet orice whereby the incoming air is diffused laterally in a substantially annular manner toward the sides of the mask; a loosely swinging valve adjacent to thel exhaust opening adapted to close the latter during inhalationby the wearer; and a tube connected with the air supply and extending into'the mask with a discharge opening disposed so as to direct an air jet toward the exhaust opening.

2. An air mask of the character described com-725 prising a shell open at one side to fit about the: nose and mouth of the user while the opposite wall is provided with an exhaust opening; a downwardly opening hood over said opening; air conveying means secured to and terminating in thew bottom wall of the shell in an annular opening, a portion of said means permitting the air to expand before delivery into the shell for inhalation, while a second portion of said means extends upwardly into the shell with a forwardly disposed discharge opening so as to direct a jet of air toward said exhaust opening; a gravity seating disc at the air inlet orifice of said iirst portion whereby the incoming air is diffused circumferentially laterally; a swinging valve pivotally secured at its upper end in said hood so as to depend across the exhaust opening; and yielding means for limiting the movement of the valve away from the exhaust opening.

HENRY A. BRAND. s 

